Light emitting panel and light emitting display

ABSTRACT

A light emitting display includes a pixel circuit. The pixel circuit includes a power electrode line, a capacitor for charging a voltage corresponding to a data signal, a driving transistor for outputting a current corresponding to the voltage charged in the capacitor, and emit elements for emitting lights corresponding to the current output by the driving transistor. One or more emit control transistors are coupled between the driving transistor and the emit elements, and selectively applies the current output by the driving transistor to the emit elements. The power electrode line is provided at an area between the emit elements.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2004-0029921, filed on Apr. 29, 2004, which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a displaying device, and moreparticularly, to an organic electroluminescent (EL) display usingelectroluminescence of an organic matter.

2. Discussion of the Related Art

In general, an organic EL display is a displaying device forelectrically exciting phosphorous organic compounds to emit light. Theorganic EL display drives n×m organic light emitting elements arrangedin a matrix format to represent images.

The organic light emitting elements have diode characteristics so theymay be referred to as organic light emitting diodes (OLEDs), and have astructure including an anode electrode layer (ITO), an organic thin-filmlayer, and a cathode electrode layer (metallic). The organic thin filmhas a multi-layered structure including an emitting layer (EML), anelectron transport layer (ETL), and a hole transport layer (HTL) tobalance electrons and holes and improve light emission efficiency, andit additionally has an electron injecting layer (EIL) and a holeinjecting layer (HIL). The organic light emitting elements form anorganic EL display panel through an arrangement in an n×m matrix format.

Methods for driving the organic EL display panel include a passivematrix method, and an active matrix method which uses thin-filmtransistors (TFTs). The passive matrix method forms anodes and cathodesto cross (or cross over) with (or to be substantially perpendicular to)each other, and selects lines to drive organic EL elements. The activematrix method sequentially turns on a plurality of TFTs coupled to datalines and scan lines according to scan select signals to thus driveorganic EL elements.

A pixel circuit of a general active matrix organic EL display will bedescribed.

FIG. 1 shows one of n×m pixels, that is, equivalently illustrating apixel provided on the first row and the first column.

As shown in FIG. 1, a pixel 10 has three sub-pixels 10 r, 10 g, and 10 bwhich have organic EL elements OLEDr, OLEDg, and OLEDb respectivelyemitting red, green, and blue (RGB) lights. In the case of sub-pixelsarranged in a stripe pattern, the sub-pixels 10 r, 10 g, and 10 b arecoupled to data lines D1 r, D1 g, and D1 b, and a common scan line S1.

The red sub-pixel 10 r includes transistors M11 r and M12 r and acapacitor C1 r for driving the organic EL element OLEDr. Likewise, thegreen sub-pixel 10 g includes transistors M11 g and M12 g and acapacitor C1 g, and the blue sub-pixel 10 b includes transistors M11 band M12 b and a capacitor C1 b. The connection and operation of only thesub-pixel 10 r will now be described since the connections andoperations of the sub-pixels 10 r, 10 g, and 10 b are substantially thesame.

The driving transistor M11 r is coupled between a power supply voltageof VDD and an anode of the organic EL element OLEDr to transmit a lightemitting current to the organic EL element OLEDr, and a cathode of theorganic EL element OLEDr is coupled to a voltage of VSS, which is lowerthan the power supply voltage of VDD. The current of the drivingtransistor M11 r is controlled by a data voltage applied through thetransistor M12 r. In this instance, the capacitor C1 r is coupledbetween a source and a gate of the transistor M11 r to maintain theapplied voltage for a predetermined time. A gate of the transistor M12 ris coupled to the scan line S1 for transmitting an on/off-type selectsignal, and a source of the transistor M12 r is coupled to the data lineD1 r for transmitting a data voltage corresponding to the red sub-pixel10 r.

In operation, when the switching transistor M12 r is turned on inresponse to a select signal applied to the gate, a data voltage of VDATAprovided by the data line D1 r is applied to the gate of the transistorM11 r. A current (I_(OLED)) flows to (and/or through) the transistor M11r in correspondence to a voltage charged between the gate and the sourceby the capacitor C1 r, and the organic EL element OLEDr emits light incorrespondence to the current (I_(OLED)). In this instance, the current(I_(OLED)) flowing to the organic EL element OLEDr is given in Equation1.

$\begin{matrix}{I_{OLED} = {{\frac{\beta}{2}( {V_{GS} - V_{TH}} )^{2}} = {\frac{\beta}{2}( {V_{DD} - V_{DATA} - {V_{TH}}} )^{2}}}} & {{Equation}\mspace{20mu} 1}\end{matrix}$

where V_(TH) is a threshold value of the transistor M11 r, and β is aconstant.

As can be derived by Equation 1, in the pixel circuit shown in FIG. 1, acurrent corresponding to the data voltage is supplied to the organic ELelement OLEDr, and the organic EL element OLEDr emits light with abrightness corresponding to the supplied current. In this instance, theapplied data voltage has plural values within a predetermined range inorder to represent gray scales.

As described, the organic EL display allows one pixel 10 to have threesub-pixels 10 r, 10 g, and 10 b, each of which includes a drivingtransistor, M11 r, M11 g, or M11 b, a switching transistor, M12 r, M12g, or M12 b, and a capacitor, C1 r, C1 g, and C1 b, for driving anorganic EL element. Also, a data line, D1 r, D1 g, or D1 b, fortransmitting data signals and a power electrode line for transmittingthe power supply voltage of VDD are provided for each sub-pixel.

Therefore, the number of transistors, capacitors, and wires fortransmitting voltages and signals is increased so that it is difficultto lay out all of them in the pixels, and aperture ratios correspondingto light-emitted areas in the pixels are decreased (i.e., a ratiobetween the bright pixel area and the pixel area that is blocked by theparts to drive each pixel is decreased).

SUMMARY OF THE INVENTION

An aspect of the present invention provides a light emitting displayhaving an efficient arrangement of structures corresponding to pixelareas.

One exemplary embodiment of the present invention provides a displaydevice. The display device includes a plurality of scan lines, which areprovided in a first direction and for transmitting select signals, aplurality of data lines, which are provided in a second direction andinsulatively cross the scan lines, and for transmitting data signals,and a plurality of pixel circuits, which are respectively coupled to thescan lines and the data lines. At least one of the pixel circuitsincludes a power electrode line, a capacitor, a first transistor, afirst emit element, a second emit element, a first emit controltransistor, and a second emit control transistor. The power electrodeline is provided in the second direction and supplies a power voltage.The capacitor has a first capacitor electrode coupled to the powerelectrode line, and charges a voltage corresponding to at least one ofthe data signals. The first transistor has a first electrode coupled tothe power electrode line, and a second electrode for outputting acurrent corresponding to the voltage charged in the capacitor. The firstemit element and the second emit element output lights corresponding tothe current output by the first transistor. The first emit controltransistor and the second emit control transistor are respectivelycoupled between the second electrode of the first transistor and thefirst and second emit elements, and selectively apply the current outputby the first transistor to the first and second emit elements. The powerelectrode line is provided at an area between the first and second emitelements.

The data line may be provided at an area between another pixel areaadjacent to the pixel area and the pixel area.

The emit elements may be substantially rectangular in shape, and mayhave short axes in the first direction and long axes in the seconddirection. The long axes may be longer than the short axes, and at leastone of the long axes of the first emit element may be adjacent to atleast one of the long axes of the second emit element.

The data line may be provided adjacent to at least another one of thelong axes of the first emit element, and the data line may be separatedfrom the second emit element by the first emit element.

One exemplary embodiment of the present invention provides a lightemitting display. The light emitting display includes a plurality ofscan lines, which are provided in a first direction and for transmittingselect signals, a plurality of data lines, which are provided in asecond direction and insulatively cross the scan lines, and fortransmitting data signals, and a plurality of pixel circuits, which arerespectively coupled to the scan lines and the data lines, the seconddirection being substantially perpendicular to the first direction. Apixel area in which at least one of the pixel circuits is providedincludes: a power electrode line, a first capacitor, a first transistor,a first emit element, a second emit element, a third emit element, afirst emit control transistor, a second emit control transistor, and athird emit control transistor. The power electrode line is provided inthe second direction and supplies a power voltage. The first capacitorhas a first capacitor electrode coupled to the power electrode line, andcharges a voltage corresponding to at least one of the data signals. Thefirst transistor has a first electrode coupled to the power electrodeline, and a second electrode for outputting a current corresponding tothe voltage charged in the capacitor. The first emit element, a secondemit element, and a third emit element output lights corresponding tothe current output by the first transistor. The first emit controltransistor, the second emit control transistor, and the third emitcontrol transistor are respectively coupled between the second electrodeof the first transistor and the first, second, and third emit elements,and selectively apply the current output by the first transistor to thefirst, second, and third emit elements. The power electrode line isprovided to an area between the first and second emit elements and/or anarea between the second and third emit elements.

The pixel area may further include a second capacitor, a secondtransistor, and a third transistor. The second capacitor is coupledbetween a second capacitor electrode of the first capacitor and acontrol electrode of the first transistor, and charges a voltagecorresponding to a threshold voltage of the first transistor. The secondtransistor is coupled between the control electrode of the firsttransistor and the first emit control transistor, the second emitcontrol transistor, and the third emit control transistor and/ordiode-connects the first transistor. The third transistor includes athird electrode coupled to the control electrode of the firsttransistor, and a fourth electrode coupled to the power electrode line.

One exemplary embodiment of the present invention provides a displaypanel. The display panel includes a plurality of scan lines, a pluralityof data lines, a first emit element, a second emit element, and a powerelectrode line. The scan lines are provided in a first direction and fortransmitting select signals. The data lines are provided in a seconddirection and insulatively cross the scan lines, and for transmittingdata signals. The first emit element and the second emit element areprovided in parallel and between two adjacent data lines from among thedata lines. The power electrode line is provided in parallel with thedata lines and at an area between the first and second emit elements.

The first and second emit elements may be substantially rectangular inshape and have short axes in the first directions and long axes in thesecond directions, the long axes may be longer than the short axes, andthe long axes may be adjacent and parallel with each other.

One exemplary embodiment of the present invention provides a lightemitting display panel. The light emitting display panel includes: aplurality of scan lines, a plurality of data lines, a first emitelement, a second emit element, a third emit element, and a first powerelectrode line. The scan lines are provided in a first direction and fortransmitting select signals. The data lines are provided in a seconddirection and insulatively cross the scan lines, and for transmittingdata signals. The first emit element, the second emit element, and thethird emit element are provided between two adjacent data lines fromamong the data lines. The first power electrode line is provided inparallel with the data line and to an area between the first and secondemit elements and/or an area between the second and third emit elements.

The first power electrode line may be provided at the area between thefirst and second emit elements.

The light emitting display panel may further include a second powerelectrode line formed between the second and third emit elements, and abridge electrode line for coupling the first and second power electrodelines.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, together with the specification, illustrateexemplary embodiments of the present invention, and, together with thedescription, serve to explain the principles of the present invention.

FIG. 1 shows a conventional pixel circuit of a light emitting displaypanel;

FIG. 2 shows a schematic diagram for an organic EL display according toa first exemplary embodiment of the present invention;

FIG. 3 shows an equivalent circuit diagram of a pixel circuit accordingto the first exemplary embodiment of the present invention;

FIG. 4 shows an arrangement diagram for the pixel area according to thefirst exemplary embodiment of the present invention;

FIG. 5 shows a cross-sectional view with respect to the part of I to I′in FIG. 4;

FIG. 6 shows a cross-sectional view with respect to the part of II toII′ in FIG. 4;

FIG. 7 shows an arrangement diagram for the pixel area according to asecond exemplary embodiment of the present invention;

FIG. 8 shows an arrangement diagram for the pixel area according to athird exemplary embodiment of the present invention; and

FIG. 9 shows an arrangement diagram for the pixel area according to afourth exemplary embodiment of the present invention.

DETAILED DESCRIPTION

In the following detailed description, only certain exemplaryembodiments of the present invention are shown and described, by way ofillustration. As those skilled in the art would recognize, the describedexemplary embodiments may be modified in various ways, all withoutdeparting from the spirit or scope of the present invention.Accordingly, the drawings and description are to be regarded asillustrative in nature, rather than restrictive.

There may be parts shown in the drawings, or parts not shown in thedrawings, that are not discussed in the specification as they are notessential to a complete understanding of the invention. Like referencenumerals designate like elements.

As to jargon on the scan lines, a scan line for transmitting a currentselect signal will be referred to as a “current scan line,” a scan linewhich has transmitted a select signal before the current select signalis transmitted will be referred to as a “previous scan line,” and aselect signal after the current select signal is transmitted will bereferred to as a “subsequent scan line.”

In addition, a pixel which emits light based on the select signal of thecurrent scan line will be referred to as a “current pixel,” a pixelwhich emits light based on the select signal of the previous scan linewill be referred to as a “previous pixel,” and a pixel which emits lightbased on the select signal of the subsequent scan line will be referredto as a “subsequent pixel.”

Exemplary embodiments of the present invention will now be described indetail with reference to the drawings.

FIG. 2 shows a configuration of an organic EL display according to afirst exemplary embodiment of the present invention.

As shown, the organic EL display includes a display panel 100, a scandriver 200, an emit controller 300, and a data driver 400. The displaypanel 100 includes a plurality of scan lines S0, S1, . . . , Sk, . . . ,Sn and emit control lines E1, . . . , Ek, . . . , En provided in the rowdirection, a plurality of data lines D1, . . . , Dk, . . . , Dm providedin the column direction, a plurality of power electrode lines fortransmitting the voltage of VDD, and a plurality of pixels 110. A pixel110 is formed at a pixel area generated by two scan lines Sk-1 and Skand two adjacent data lines Dk-1 and Dk, and is driven by signalstransmitted by the current scan line Sk, the previous scan line Sk-1,the emit control line Ek, and the data line Dk. The emit control linesE1 to En respectively include three emit control lines for emitting red,green, and blue (RGB) colors (e.g., E1 includes E1 r, E1 g, and E1 b andEn includes Enr, Eng, and Enb).

The scan driver 200 sequentially transmits select signals for selectinglines to the scan lines S0 to Sn so that data signals may be applied topixels of the corresponding selected scan lines, the emit controller 300sequentially transmits emit control signals for controlling emission ofthe organic EL elements OLEDr, OLEDg, and OLEDb shown in FIG. 3 to theemit control lines E1 to En, and the data driver 400 applies datasignals, which correspond to the pixels of the selected scan lines towhich the select signals are applied, to the data lines D1 to Dm whenthe select signals are sequentially applied.

The scan driver 200, the emit controller 300, and the data driver 400can be coupled to a substrate on which the display panel 100 isprovided. Alternatively, the scan driver 200, the emit controller 300,and/or the data driver 400 can be directly installed on a glasssubstrate of the display panel 100, or can be replaced with a drivingcircuit formed on the same layer as that of the scan lines, the datalines, and the transistors on the substrate of the display panel 100.Further, the scan driver 200, the emit controller 300, and/or the datadriver 400 can be mounted in a chip format on a tape carrier package(TCP) or a flexible printed circuit (FPC) coupled to the substrate ofthe display panel 100.

In addition, a field can be divided into three subfields which are thendriven, and the three subfields program red, green, and blue data andemit lights. To achieve this purpose, the scan driver 200 sequentiallytransmits a select signal to the scan lines S0 to Sn for each subfield,the emit controller 300 applies an emit control signal to the emitcontrol lines E1 to En so that the organic EL elements of respectivecolors may emit light in a subfield, and the data driver 400 appliesdata signals corresponding to the red, green, and blue organic ELelements to the data lines D1 to Dm in the three subfields.

An operation of the organic EL display according to the first exemplaryembodiment of the present invention will be described in detail withreference to FIG. 3.

FIG. 3 shows an equivalent circuit diagram of the pixel 110 in theorganic EL display shown in FIG. 2. For ease of description, the pixelPk coupled to the scan line Sk of the k-th row and the data line Dk ofthe k-th column is exemplarily illustrated, and p-channel transistorsare shown by way of example in FIG. 3.

As shown in FIG. 3, the pixel circuit includes a driving transistor M1,a diode transistor M3, a capacitor transistor M4, a switching transistorM5, organic EL elements OLEDr, OLEDg, and OLEDb, emit controltransistors M2 r, M2 g, and M2 b for controlling emission of the organicEL elements OLEDr, OLEDg, and OLEDb, and capacitors Cst and Cvth. Oneemit control line Ek shown in FIG. 2 includes emit control lines Ekr,Ekg, and Ekb. The emit control transistors M2 r, M2 g, and M2 b respondto emit control signals transmitted by the emit control lines Ekr, Ekg,and Ekb, and selectively transmit the current provided by the drivingtransistor M1 to the organic EL elements OLEDr, OLEDg, and OLEDb.

In detail, the transistor M5 has a gate coupled to the current scan lineSk and a source coupled to the data line Dk, and the transistor M5responds to the select signal provided by the scan line Sk and transmitsthe data voltage provided by the data line Dk to a node B of thecapacitor Cvth. The transistor M4 responds to the select signal providedby the previous scan line Sk-1 and couples the node B of the capacitorCvth to the power supply voltage VDD. The transistor M3 is coupled to anode A of the capacitor Cvth and is also coupled to the organic E1elements OLEDr, OLEDg, and OLEDb through the transistors M2 r, M2 g, andM2 b, respectively. The transistor M3 responds to the select signalprovided by the previous scan line Sk-1 and diode-connects thetransistor M1. The driving transistor M1 for driving the organic ELelement OLED has a gate coupled to the node A of the capacitor Cvth anda source coupled to the power voltage VDD, and controls the current tobe applied to the organic EL element OLED (e.g., OLEDr, OLEDg, and/orOLEDb) according to the voltage applied to the gate.

Also, the capacitor Cst has a first electrode coupled to the powersupply voltage VDD and a second electrode coupled to a drain electrodeof the transistor M4 (e.g., at around the node B), and the a firstelectrode or Node B of the capacitor Cvth is coupled to the secondelectrode of the capacitor Cst to thus couple the two capacitors inseries, and a second electrode or node A of the capacitor Cvth iscoupled to the gate electrode of the driving transistor M1 (e.g., ataround the node A).

The drain of the driving transistor M1 is coupled to sources of the emitcontrol transistors M2 r, M2 g, and M2 b, which have gates respectivelycoupled to the emit control lines Ekr, Ekg, and Ekb. The emit controltransistors M2 r, M2 g, and M2 b have drains respectively coupled toanodes of the organic EL elements OLEDr, OLEDg, and OLEDb which havecathodes to which the power supply voltage VSS of less than the powersupply voltage VDD is applied. A negative voltage or a ground voltagecan be used for the power supply voltage VSS.

In operation, when a low-level scan voltage is applied to the previousscan line Sk-1, the transistors M3 and M4 are turned on. When thetransistor M3 is turned on the transistor M1 is diode-connected.Therefore, a voltage difference between the gate and the source of thetransistor M1 is varied until the voltage difference reaches a thresholdvoltage (Vth) of the transistor M1. Since the source of the transistorM1 is coupled to the power supply voltage VDD in this instance, thevoltage applied to the gate of the transistor M1, that is, the node A ofthe capacitor Cvth, becomes a sum of the power supply voltage VDD andthe threshold voltage (Vth). Further, the transistor M4 is turned on toapply the power supply voltage VDD to the node B of the capacitor Cvth.As such, a voltage (Vcvth) charged in the capacitor Cvth is given inEquation 2.V _(Cvth) =V _(CvthA) −V _(CvthB)=(VDD+V _(th))−VDD=V _(th)  Equation 2

where V_(Cvth) is a voltage charged in the capacitor Cvth, V_(CvthA) isa voltage applied to the node A of the capacitor Cvth, and V_(CvthB) isa voltage applied to the node B of the capacitor Cvth.

When a low-level scan voltage is applied to the current scan line Sk,the transistor M5 is turned on to apply the data voltage (Vdata) to thenode B. Also, since the capacitor Cvth is charged with the voltagecorresponding to the threshold voltage (Vth) at the transistor M1, thevoltage corresponding to the sum of the data voltage (Vdata) and thethreshold voltage (Vth) at the transistor M1 is applied to the gate ofthe transistor M1. That is, a voltage (Vgs) between the gate and thesource of the transistor M1 is given in Equation 3. In this instance, ahigh-level signal is applied to the emit control line Ek (e.g., Ekr,Ekg, and/or Ekb), and the transistor M2 (e.g., M2 r, M2 g, and/or M2 b)is turned off to block a current flow.V _(gs)=(V _(data) +V _(th))−VDD  Equation 3

Next, the transistor M2 is turned on in response to a low-level signalof the emit control line Ek, the current (I_(OLED)) corresponding to thegate-source voltage of Vgs at the transistor M1 is supplied to theorganic EL element OLED through the transistor M2, and the organic ELelement OLED (e.g., OLEDr, OLEDg, and/or OLEDb) emits light. The current(I_(OLED)) is given in Equation 4.

$\begin{matrix}{I_{OLED} = {{\frac{\beta}{2}( {V_{gs} - V_{th}} )^{2}} = {{\frac{\beta}{2}( {( {V_{data} + V_{th} - {VDD}} ) - V_{th}} )^{2}} = {\frac{\beta}{2}( {{VDD} - V_{data}} )^{2}}}}} & {{Equation}\mspace{20mu} 4}\end{matrix}$

-   -   where I_(OLED) is a current flowing to the organic EL element,        V_(gs) is a voltage between the source and the gate of the        transistor M1, V_(th) is a threshold voltage of the transistor        M1, V_(data) is a data voltage, and β is a constant.

In more detail, when the emit control transistor M2 r is turned on inresponse to the low-level emit control signal provided by the emitcontrol line Ekr the data voltage (Vdata) represents a red data signaland the current (I_(OLED)) is transmitted to the red organic EL elementOLEDr, which then emits light.

Likewise, when the emit control transistor M2 g is turned on in responseto the low-level emit control signal provided by the emit control lineEkg, the data voltage (Vdata) represents a green data signal and thecurrent (I_(OLED)) is transmitted to the green organic EL element OLEDg,which then emits light. Also, when the emit control transistor M2 b isturned on in response to the low-level emit control signal provided bythe emit control line Ekb, the data voltage (Vdata) represents a bluedata signal and the current (I_(OLED)) is transmitted to the blueorganic EL element OLEDb, which then emits light. The three lightcontrol signals applied to the three emit control lines Ekr, Ekg, andEkb respectively have a low-level period which is not superimposed onone another so that one pixel may represent red, green, and blue.

Referring to FIGS. 4 to 6, an arrangement structure of a pixel area inwhich a pixel circuit is provided in the organic EL display according tothe first exemplary embodiment of the present invention will bedescribed. Herein, certain components of the current pixel Pk will havenormal reference numerals, and certain components of the previous pixelPk-1 will have apostrophe-added reference numerals (“′”) to thusdistinguish the certain components of the current pixel and the certaincomponents of the previous pixel.

FIG. 4 shows an exemplified arrangement diagram for a pixel areaaccording to the first exemplary embodiment of the present invention,FIG. 5 shows a cross-sectional view with respect to the part of I to I′in FIG. 4, and FIG. 6 shows a cross-sectional view with respect to thepart of II to II′ in FIG. 4.

As shown by FIGS. 4 to 6, a shield layer 3 of silicon oxide is formed onan insulation substrate 1, and polysilicon layers 21, 22, 23, 24, 25,26, 27, and 28, which are semiconductor layers, are formed on the shieldlayer 3.

A U-shaped polysilicon layer 21 forms a semiconductor layer including asource region, a drain region, and a channel region of the transistor M5of the current pixel Pk. The polysilicon layers 22, 23, 24, 25, 26, 27,and 28 are formed in a body or as a single unit. The polysilicon layer27 is extended in the column direction between the emit elements OLEDr′and OLEDg′ of the previous pixel Pk-1 to form the node A, which is anelectrode or a first electrode of the capacitor Cvth. The polysiliconlayer 28 is extended in a column direction between the emit elementsOLEDg′ and OLEDb′ of the previous pixel Pk-1 to form an electrode of thecapacitor Cst. The polysilicon layer 26 is adjacent to the emit elementsOLEDg′ and OLEDb′ and is extended in a row direction with the horizontalwidth of the emit elements OLEDg′ and OLEDb′ to form a semiconductorlayer of the transistors M1, M3, and M4. The polysilicon layer 25 iscoupled to the polysilicon layer 26 on about the center of therow-directional width of a pixel area, that is, on about the center ofthe horizontal width of the emit elements OLEDr′, OLEDg′, and OLEDb′.The polysilicon layer 25 is formed in the column direction, and forms adrain region of the transistor M1 and source regions of the transistorsM2 r, M2 g, and M2 b. The polysilicon layers 22, 23, and 24 are branchedout from the polysilicon layer 25 to form an ‘m’ pattern and form drainregions of the transistors M2 r, M2 g, and M2 b.

A gate insulation film 30 is formed on the above-formed polysiliconlayers 21, 22, 23, 24, 25, 26, 27, and 28.

Gate electrode lines 41, 42, 43, 44, 45, 46, and 47 are formed on thegate insulation film 30. In more detail, since the gate electrode line41 is extended in the row direction and corresponds to the current scanline Sk of the current pixel Pk, the gate electrode line 41 insulativelycrosses the polysilicon layer 21 and forms a gate electrode of thetransistor M5 of the current pixel Pk. Since the gate electrode line 42is extended in the row direction and corresponds to the emit controlline Ekb of the current pixel Pk, the gate electrode line 42 forms agate electrode of the transistor M2 b. Since the gate electrode line 43is extended in the row direction and corresponds to the emit controlline Ekg of the current pixel Pk, the gate electrode line 43 forms agate electrode of the transistor M2 g. Since the gate electrode line 44is extended in the row direction and corresponds to the emit controlline Ekr of the current pixel Pk, the gate electrode line 44 forms agate electrode of the transistor M2 k. Since the gate electrode line 45is extended in the row direction and corresponds to the previous scanline Sk-1 of the previous pixel Pk-1, the gate electrode line 45insulatively crosses the polysilicon layer 21′ and forms a gateelectrode of the transistor M5′ of the previous pixel Pk-1. Also, thegate electrode line 45 insulatively crosses the polysilicon layer 25 andforms gate electrodes of the transistors M3 and M4 of the current pixelPk. The gate electrode 46 insulatively crosses the polysilicon layer 26in a rectangular manner on the bottom of the emit element OLEDg′ to forma gate electrode of the transistor M1. The gate electrode 47 is formedin a U shape and is provided between the emit elements OLEDr′ and theOLEDg′ and between the emit elements OLEDg′ and the OLEDb′, and forms anode B on which the capacitors Cvth and Cst are coupled in series.Therefore, as shown in FIG. 6, a portion of the gate electrode 47 issuperimposed on the polysilicon layer 27 to become an electrode of thecapacitor Cvth, and another portion of the gate electrode 47 issuperimposed on the polysilicon layer 28 to become an electrode of thecapacitor Cst.

Referring now back to FIGS. 4 to 6, an inter-layer insulation film 50 isformed on the gate electrodes 41, 42, 43, 44, 45, 46, and 47. A powerelectrode line 61, a data line 62, and electrodes 63, 64, and 65 areformed on the inter-layer insulation film 50 and are coupled to thecorresponding electrodes through contact holes 51 a, 51 b, 52, 53, 54 a,55 a, 55 b, 57 r, 57 g, and 57 b.

The power electrode line 61 is extended in the column direction betweenthe emit elements OLEDg and OLEDb, and is coupled to the polysiliconlayers 28 and 26 through a contact hole 54 b, which penetrates theinter-layer insulation film 50 and the gate insulation film 30, tosupply power to the first electrode of the capacitor Cst and the sourceof the transistor M1.

The data line 62 is extended in the column direction between a pixelarea and another pixel area, and is coupled to the polysilicon layer 21through a contact hole 51 a which penetrates the inter-layer insulationfilm 50 and the gate insulation film 30, and is coupled to the source ofthe transistor M4.

The electrode 63 couples the polysilicon layer 21 and the gate electrode47 through the contact hole 51 b, which penetrates the inter-layerinsulation film 50 and the gate insulation film 30, and a contact hole52, which penetrates the inter-layer insulation film 50, and becomes thenode B.

The electrode 64 couples the drain of the transistor M3 of thepolysilicon layer 26 and the gate electrode 46 through the contact hole53, which penetrates the inter-layer insulation film 50 and the gateinsulation film 30, and the contact hole 54 a, which penetrates theinter-layer insulation film 50, and becomes the node A.

The electrode 65 couples the drain of the transistor M4 of thepolysilicon layer 25 and the gate electrode 47 through the contact hole55 a, which penetrates the inter-layer insulation film 50, and thecontact hole 55 b, which penetrates the inter-layer insulation film 50and the gate insulation film 30, and becomes the node B.

The electrodes 71 r, 71 g, and 71 b are pixel electrodes of therespective emit elements. The pixel electrodes 71 r, 71 g, and 71 b arerespectively coupled to the polysilicon layers 22, 23, and 24 throughthe contact holes 57 r, 57 g, and 57 b, which penetrate the gateinsulation film 30 and the inter-layer insulation film 50, and are thencoupled respectively to the drain electrodes of the transistors M2 r, M2g, and M2 b.

The pixel electrodes 71 r, 71 g, and 71 b of emit elements OLEDr, OLEDg,and OLEDb are formed to be a rectangle in which the vertical line of therectangle parallel to the data line 62 is longer than the horizontalline of the rectangle parallel to the gate electrodes 42 to 44, andhence, the longer vertical lines of the emit elements OLEDr, OLEDg, andOLEDb are arranged near each other.

As described above, the capacitor Cvth of FIG. 3 has a first electrodebeing the polysilicon layer 27 and a second electrode being the gateelectrode 47, and is formed between the organic EL elements OLEDr′ andOLEDg′. The capacitor Cst of FIG. 3 has the first electrode being thegate electrode 47 and the second electrode being the polysilicon layer28 coupled to the power electrode line 61 and is formed between theorganic EL elements OLEDg′ and OLEDb′.

By arranging the power electrode line 61 on the area between the emitelements OLEDg and OLEDb, the source of the driving transistor M1, thesource of the transistor M4, and the first electrode of the powerelectrode line 61 are directly coupled with each other withoutadditional extended wiring. As such, power is supplied to the drivingtransistors M1 and M4 and the capacitor Cst without reducing theaperture ratios of the organic EL elements or emit elements OLEDr,OLEDg, and OLEDb (i.e., the ratio between the bright pixel area and thepixel area that is blocked is increased).

A second exemplary embodiment of the present invention will bedescribed.

FIG. 7 shows an arrangement diagram for the pixel area according to thesecond exemplary embodiment of the present invention.

As shown, the pixel area according to the second exemplary embodiment isdifferent from that of the first exemplary embodiment in that a secondpower electrode line 66 provided in parallel with the power electrodeline 61 and between the emit elements OLEDr and OLEDg (or between OLEDr′and OLEDg′) and a bridge electrode line 67 for coupling the first andsecond power electrode lines 61 and 66 are further provided in the pixelarea according to the second embodiment.

In operation, by providing double power electrode lines for the currentto pass through; the influence of a voltage drop caused by an internalresistance of components in the second exemplary embodiment is less thanthat of components in the first exemplary embodiment. Hence, the poweris more stably supplied to the respective pixel areas in the secondexemplary embodiment.

However, in the second exemplary embodiment, since the bridge electrodeline 67 is formed in the horizontal direction, areas superimposed on thegate electrodes 42, 43, and 44 by the bridge electrode line 67 aredifferent, and hence, since different loads are applied to the gateelectrodes 42, 43, and 44 by the bridge electrode line 67,characteristics of the transistors M2 r, M2 g, and M2 b may be varied.

A third exemplary embodiment in which the gate electrodes 42, 43, and 44have the same load will now be described.

FIG. 8 shows an arrangement diagram for the pixel area according to thethird exemplary embodiment of the present invention. The arrangementconfiguration according to the third exemplary embodiment is differentfrom that of the second exemplary embodiment in that a bridge electrodeline 67 a for coupling the first and second power electrode lines 61 and66 is formed in a diagonal direction.

Therefore, as shown in FIG. 8, an area A where the bridge electrode line67 a crosses the gate electrode 44, an area B where the bridge electrodeline 67 a crosses the gate electrode 43, and an area C where the bridgeelectrode line 67 a crosses the gate electrode 42 are formed to be thesame in the arrangement configuration according to the third exemplaryembodiment.

FIG. 9 shows an arrangement diagram for the pixel area according to afourth exemplary embodiment of the present invention. The arrangementconfiguration according to the fourth exemplary embodiment is differentfrom that of the third embodiment in that a bridge electrode line 67 bfor coupling the first and second power electrode lines 61 and 66 isformed in a staircase manner.

Therefore, as shown in FIG. 9, an area A where the bridge electrode line67 b crosses the gate electrode 44, an area B where the bridge electrodeline 67 b crosses the gate electrode 43, and an area C where the bridgeelectrode line 67 b crosses the gate electrode 42 are formed to be thesame in the arrangement configuration according to the fourth exemplaryembodiment.

Accordingly, by making the bridge electrode lines 67 a and/or 67 b crossthe gate electrodes 42, 43, and 44 in a diagonal direction and/or in astaircase manner, the bridge electrode lines 67 a and 67 b of the thirdand fourth exemplary embodiments, respectively, apply the same load tothe gate electrodes 42, 43, and 44. Therefore, the characteristics ofthe transistors M2 r, M2 g, and M2 b are uniformly maintained.

Certain exemplary embodiments of the present invention have beenexemplified by a pixel circuit which includes five transistors, twocapacitors, and three emit elements, however, the present invention isnot thereby limited. Embodiments of the present invention can beapplicable to a pixel circuit having one emit element, two emitelements, four emit elements, and/or more than four emit elements andcan also be applicable to a pixel circuit with one, two, and/or moretransistors, and/or one or more capacitors (e.g., the two transistorsand one capacitor embodiment of FIG. 1).

In view of the foregoing, certain exemplary embodiments of the presentinvention provide parts of a pixel within a pixel area that areefficiently arranged by providing a power electrode line between emitelements of the pixel having the plural emit elements.

While the invention has been described in connection with certainexemplary embodiments, it is to be understood by those skilled in theart that the invention is not limited to the disclosed embodiments, but,on the contrary, is intended to cover various modifications includedwithin the spirit and scope of the appended claims and equivalentsthereof.

1. A display device including a plurality of scan lines, which areprovided in a first direction and for transmitting select signals, aplurality of data lines, which are provided in a second direction andinsulatively cross the scan lines, and for transmitting data signals,and a plurality of pixel circuits, which are respectively coupled to thescan lines and the data lines, wherein at least one of the pixelcircuits comprises: a power electrode line, which is provided in thesecond direction and for supplying a power voltage; a capacitor having afirst capacitor electrode coupled to the power electrode line, and forcharging a voltage corresponding to at least one of the data signals; afirst transistor having a first electrode coupled to the power electrodeline, and a second electrode for outputting a current corresponding tothe voltage charged in the capacitor; a first emit element and a secondemit element for outputting lights corresponding to the current outputby the first transistor; and a first emit control transistor and asecond emit control transistor respectively coupled between the secondelectrode of the first transistor and the first and second emitelements, and for selectively applying the current output by the firsttransistor to the first and second emit elements, wherein the powerelectrode line is provided at an area between the first and second emitelements.
 2. The display device of claim 1, wherein the data line isprovided at an area between another pixel area adjacent to the pixelarea and the pixel area.
 3. The display device of claim 2, wherein theemit elements are substantially rectangular in shape, and have shortaxes in the first direction and long axes in the second direction, thelong axes being longer than the short axes, and at least one of the longaxes of the first emit element is adjacent to at least one of the longaxes of the second emit element.
 4. The display device of claim 3,wherein the data line is provided adjacent to at least another one ofthe long axes of the first emit element and wherein the data line isseparated from the second emit element by the first emit element.
 5. Alight emitting display including a plurality of scan lines, which areprovided in a first direction and for transmitting select signals, aplurality of data lines, which are provided in a second direction andinsulatively cross the scan lines, and for transmitting data signals,and a plurality of pixel circuits, which are respectively coupled to thescan lines and the data lines, the second direction being substantiallyperpendicular to the first direction, wherein a pixel area in which atleast one of the pixel circuits is provided comprises: a power electrodeline, which is provided in the second direction and for supplying apower voltage; a first capacitor having a first capacitor electrodecoupled to the power electrode line, and for charging a voltagecorresponding to at least one of the data signals; a first transistorhaving a first electrode coupled to the power electrode line, and asecond electrode for outputting a current corresponding to the voltagecharged in the capacitor; a first emit element, a second emit element,and a third emit element for outputting lights corresponding to thecurrent output by the first transistor; and a first emit controltransistor, a second emit control transistor, and a third emit controltransistor respectively coupled between the second electrode of thefirst transistor and the first, second, and third emit elements, and forselectively applying the current output by the first transistor to thefirst, second, and third emit elements, wherein the power electrode lineis provided to an area selected from at least one of an area between thefirst and second emit elements and an area between the second and thirdemit elements.
 6. The light emitting display of claim 5, wherein thepixel area further comprises: a second capacitor being coupled between asecond capacitor electrode of the first capacitor and a controlelectrode of the first transistor, and for charging a voltagecorresponding to a threshold voltage of the first transistor; a secondtransistor coupled between the control electrode of the first transistorand the first emit control transistor, the second emit controltransistor, and the third emit control transistor; and a thirdtransistor including a third electrode coupled to the control electrodeof the first transistor, and a fourth electrode coupled to the powerelectrode line.
 7. The light emitting display of claim 6, furthercomprising a second power electrode line formed in parallel with thefirst power electrode line and between the second and third emitelements, wherein at least one part of the first power electrode line iselectrically coupled with at least one part of the second powerelectrode line.
 8. The light emitting display of claim 7, furthercomprising a bridge electrode line for electrically coupling the atleast one part of the first power electrode line and the at least onepart of the second power electrode line, wherein the bridge electrodeline is formed such that areas, in which the bridge electrode issuperimposed on the first, second, and third emit control transistors,substantially correspond to each other in size.
 9. The light emittingdisplay of claim 8, wherein the bridge electrode is formed to be slantedfrom the first direction with a predetermined angle.
 10. The lightemitting display of claim 8, wherein the bridge electrode is formed in astaircase manner.
 11. A display panel comprising: a plurality of scanlines, which are provided in a first direction and for transmittingselect signals; a plurality of data lines, which are provided in asecond direction and insulatively cross the scan lines, and fortransmitting data signals; a first emit element and a second emitelement provided in parallel and between two adjacent data lines fromamong the data lines; and a power electrode line provided in parallelwith the data lines and at an area between the first and second emitelements.
 12. The display panel of claim 11, wherein the first andsecond emit elements are substantially rectangular in shape and haveshort axes in the first directions and long axes in the seconddirections, wherein the long axes are longer than the short axes, andwherein the long axes are adjacent and parallel with each other.
 13. Alight emitting display panel comprising: a plurality of scan lines,which are provided in a first direction and for transmitting selectsignals; a plurality of data lines, which are provided in a seconddirection and insulatively cross the scan lines, and for transmittingdata signals; a first emit element, a second emit element, and a thirdemit element provided between two adjacent data lines from among thedata lines; and a first power electrode line provided in parallel withthe data line and to an area selected from at least one of an areabetween the first and second emit elements and an area between thesecond and third emit elements.
 14. The light emitting display panel ofclaim 13, wherein the first power electrode line is provided at the areabetween the first and second emit elements.
 15. The light emittingdisplay panel of claim 14, further comprising: a second power electrodeline disposed between the second and third emit elements; and a bridgeelectrode line for coupling the first and second power electrode lines.16. The light emitting display panel of claim 15, further comprising afirst control line, a second control line, and a third control lineprovided in the first direction at an area between at least one of thescan lines and the emit elements, and for applying respective controlsignals for controlling light emission of the emit elements, the bridgeelectrode being formed such that respective areas, in which the bridgeelectrode is superimposed on the first, second, and third control lines,substantially correspond to each other in size.
 17. The light emittingdisplay panel of claim 16, wherein the bridge electrode is formed to beslanted from the first direction with a predetermined angle.
 18. Thelight emitting display panel of claim 16, wherein the bridge electrodeis formed in a staircase manner.